ActiveX - is a technology for creating active web pages. This technology is implemented with the ActiveX control element-a dedicated program, for which the browser allocates an area of rectangular form, where this program is completely responsible for the interface with the user. The ActiveX technology supports fully automated installation. When the browser encounters an HTML link to the control element, it first checks if this element is already on the user's computer (i.e. if it was used before). If the control element is found, the browser starts it and transfers the data necessary for operation to it. If this component is not already available on the computer, the browser accesses the web address specified in the HTML document body, then downloads, installs and registers the new control element with Windows. This technology is rigidly bound to the specific operational environment of Windows 9x/NT.
Bandwidth - the maximum speed of data that can be sent or received on a connection. High bandwidth is needed to receive video or music and play it in real time.
Banner - is generally a rectangular, graphic representation of an advertisement in GIF or JPG format located on a web page with a hyperlink to the advertiser's server.
Broadcast - is a special kind of IP address used to dispatch a message to all nodes of a network. There are two forms: limited broadcast or limited broadcasting message - if every binary bit in the IP address is a 1, the package is dispatched to all network nodes from where the source of the package is. Broadcast or broadcasting message - if every binary bit in the node number in the address is a 1, then the package having such an address is dispatched to all network nodes with the specified number.
Client - is a computer or its software that accesses the Internet, as opposed to a server.
Context menu - a menu with selections that change depending on where the cursor is placed before the mouse's right button is clicked. A desktop icon's context menu is very different from a browser's web page context menu, for instance.
Cookie - is a small piece of information transferred by the server to a browser and saved on the user's computer. The browser stores this information and sometimes transfers it to the server. Some cookies are stored only during one session and deleted when the browser is closed. Other cookies are installed for an extended period.
Cracker - is someone who gains unauthorized access to a computer.
Datagram - is the unit of data, or packet, transmitted in a TCP/IP network. Each datagram contains source and destination addresses and data.
DHCP (Dynamic Host Configuration Protocol) - is a protocol intended for dynamic assignment of IP addresses. In addition to dynamic assignment, DHCP can support simpler methods of static assignment of addresses allowing addresses to be assigned both manually and automatically. DHCP can cause problems. First is the problem of coordinating the address database in DHCP and DNS services. Second is an instability of the IP addresses that complicates network control procedures.
DNS (Domain Name System) - is a system of names officially assigned to individual networks and servers on the Internet as an easier method of remembering those names than a string of IP numbers. Example: www.agnitum.com is easier to remember than the IP address 216.12.219.12. The DNS service automatically translates the name to its corresponding IP address. The DNS system requires a static configuration of its tables, which define the one to one correspondence of computer names and IP addresses.The DNS protocol is an auxiliary service protocol at the application level. This protocol is an asymmetric one - DNS servers and DNS clients are defined in it. DNS servers store a part of the distributed database that contains the correspondence of names and IP addresses. This database is distributed according to administrative domains on the Internet. Clients of the DNS server know the IP address of the server of their administrative domain and they transfer a request with the DNS name according to the IP protocol, and then wait for the IP address that corresponds to this name. If the requested information is stored in the DNS server's database, the server immediately transfers the answer to the browser. Otherwise, the server transfers a request to the DNS server of another domain, which can either process the request itself or transfer it to another DNS server. All the DNS servers are integrated in the hierarchical structure according to the domain hierarchy of the Internet. A client (browser) interrogates these name servers until it finds the necessary correspondence. The DNS database has a tree structure called a domain area of names, in which each domain (a node of the tree) has a name and can contain sub-domains. The name of a domain identifies its position in this database in relation to the parent domain, and points in the name separate parts corresponding to the domain nodes.
DNS address - is a network address of a character type, in which the names of different domains are separated from each other by a dot (.). This address corresponds to the network address in the DNS database. Example www.agnitum.com.
DoS (Denial of Service) attack - is an attack on one's computer from other computers on a network or the Internet. This type of attack takes advantage of errors in network software or protocols and results in a disturbance of the normal operating conditions of your computer.
Firewall - a software or hardware device used as a protective barrier between a computer and the network that computer is connected to.
FTP (File Transfer Protocol) - is an Internet service for transferring files from one computer to another.
Gateway - is a computer connecting two networks and transmitting packages from one network to another (the same as a router).
GGP (Gateway to Gateway Protocol) - is a protocol two gateways use to interact with one another, specifically in executing control tasks.
GRE (Generic Routing Encapsulation) - is a way to connect very different computer systems so they can exchange data.
GUI (Graphics User Interface) - is the type of software interface most computer users have come to expect in the last decade. It uses button images, icons, desktop analogy, etc. Apple's Macintosh computer is one of the first popular computers with a GUI. MS Windows is a later GUI.
HTML (HyperText Markup Language) - is a language of tags that can be embedded into a text file that a browser uses to make a fancy web page and makes it easy to browse here and there over the Internet. With HTML a web page author can combine graphics with text, enhance that text appearance and add links in the page that can supply an interaction with the person viewing that page in a browser.
ICMP (Internet Control Message Protocol) - is used to send error and control messages between computers connected on a network.
IGMP (Internet Group Management Protocol) - is used by nodes and routers to support group dispatch of messages. It informs the physical network of the nodes that are currently combined into groups and to what groups those nodes belong.
IP (Internet Protocol) - is a network-level set of Internet protocols.
IP address - is an address comprised of 4 bytes, usually represented as 4 decimal numbers separated by a dot (.). Example: 64.176.127.178. The IP address is used at the network level. A network manager assigns it when configuring computers and routers. The IP address consists of two parts: the network number and the node number. The manager can select the network number arbitrarily if the network is not connected to the Internet. Otherwise, the IP address is assigned according to recommendations made by the special Internet subdivision (Network Information Center, NIC).
IP datagram - is the unit of data, or packet, transmitted in a TCP/IP network. Each datagram contains source and destination addresses and data.
Java - the trademarked named of a programming language designed to develop applications, especially ones for the Internet, that can operate on different platforms.
Java applet - is a computer program written in the Java programming language and is embedded in a web page. Although the program is integrated directly with a web page, it is stored as a separate file.
JavaScript - is a program embedded within a web page, generally with the purpose to enhance the viewer's experience when browsing that web page.
LAN (Local Area Network) - a small network of computers usually located within one building.
Loopback - is a special IP address (127.0.0.1) reserved for feedback when testing software on a node without having to dispatch the package on the network.
Multicast - is a special group of IP addresses beginning with the sequence 255. If a multicast address is specified as an assignment address in a package, all nodes having that address will receive that package. The nodes identify themselves by which groups they belong to. The same node can be included in several groups. Such messages are called group messages. A group address is not divided into network and node number fields and is processed by a router in a special way.
NetBIOS (Network Basic Input/Output System) - is a basic network protocol developed by IBM for sharing files and printers over a network. NetBIOS is supported by IBM (IBM PC LAN), Novell NetWare, Microsoft Windows for Workgroups networks and the networks of other companies.
Network - any collection of computers connected so that data can be exchanged between them.
Node - a network connection point, such as a personal computer in a LAN or a terminal connected to a minicomputer or mainframe.
Plug-In - is an independent component that can be added or removed from a software package to extend the capability of that software. The software must be designed and built to support plug-ins. Plug-in technology allows third party developers to create plug-ins specific to that software enabling the software to do many more things.
Port - is a number corresponding to data types so that different types of data can be efficiently sent to their appropriate application programs. A port is not a physical plug or socket. It is assigned in software only.
PPTP (Point-to-Point Tunneling Protocol) - is a technology that enables very secure communications over the Internet so they cannot be intercepted.
Preset - is a pre-defined setting or group of settings for an event or action. A preset can apply many settings simultaneously with one mouse click. This saves time for users who would otherwise need to apply each setting manually.
Protocol - is a set of accepted rules for a particular type of communication interchange. When two computers are programmed to use the same protocol when transferring data between them, that data will be correctly relayed. Otherwise, if two different protocols are being used, then the transfer of data will not occur.
Proxy server - is software that manages the connection between a sender and a receiver. All input is redirected to a different port, which prevents a cracker from accessing a private network.
Referrer - is part of the HTTP request that contains the URL of the last page visited before the request.
Remote Procedure Call - a simplified method of having two computers exchange data directly into each's running applications to make these data exchanges easier for the user.
Router - is a computer connecting two networks and transmitting packages from one network to other (the same as a gateway).
RPC (Remote Procedure Call) - supports distributed applications (those apps having components located on different computers). An application issues an RPC when it needs to use a function running on another computer in the same network. It is used in client/server applications that run on MS Windows.
Server - is a computer that sends files and web pages to client computers over a network.
Service protocols - a method used by a server to update information on a client machine.
SMB (Service Message Block) - is a method of sharing network files that is used with NetBIOS. SMB works mainly through a series of client requests and server responses. SMB client and server software exists in practically all versions of Microsoft Windows.
Spyware - is hidden software or a concealed part of some software that is secretly or unknowlingly installed on your computer. Spyware collects information (usually for marketing purposes) and sends it - without the userÆs knowledge - to the author or organization that originated the spyware.
SSL (Secure Sockets Layer) - is a special protocol designed to support safe access to web servers. This is a dominating protocol for encoding exchange between a client and server.
Stateful Inspection - Stateful inspection firewall technology keeps a table of active TCP and UDP sessions and is more secure than packet filtering because it allows smaller paths along which traffic can pass.
Stealth mode - a condition by which a computer can access the Internet without letting other computers (possibly those owned by crackers) know that it is doing so.
System tray - that part of Windows' task bar that contains the time and the icons of each program that is running or that can be instantly launched.
Task bar - that part of Window's that shows a button for each running application.
TCP (Transmission Control Protocol) - is a main traffic protocol ensuring reliable delivery of information. TCP connection is always carried out between two points.
Telnet (Telecommunications Network Protocol) - is a program for linking Internet tools, such as browsers, with databases, library directories and other world-wide information resources.
Trojan horse - is a program surreptitiously placed on your computer that establishes a connection to a remote intruder. The Trojan operates under the instructions arriving from the attacker's computer or automatically transmits the information the intruder programmed it to transmit. This information is generally passwords or other confidential data stored on the user's computer.
UDP (User Datagram Protocol) - is a protocol that provides simple, low-level tools of transmission and reception of network packets directly to applications. The UDP protocol does not control the data transfer and does not define a correlation between the individual messages received or sent. Since UDP does not guarantee a reliable data transfer, applications using this protocol usually number each package and, if necessary, initialize a data retransmission. All applications that require a broadcasting or group function of IP connections should operate only with the UDP protocol.
URL (Universal Resource Locator) - is a World Wide Web universally recognized address for the identification and retrieval of resources such as a web site, a web page, an image, a video, a file, etc. A URL has the following appearance: [protocol]://host /[: port][path], where: Protocol is a protocol name such as http, ftp etc. If no protocol is specified, http is assumed. Host is the IP address or DNS address. Port is an optional parameter specifying the port number of the server. Example, with the http protocol, port 80 is generally used and is assumed if no port is specified with the http protocol. Path is the full path to the file, including its name. If the path is not specified, the server transmits its main (home) page.
VBScript - is a program embedded within a web page, generally with the purpose to enhance the viewer's experience when browsing that web page.
Virus - a piece of software, generally detrimental, that can copy itself into an application and thereby multiply from one computer to another by way of floppies or e-mail without the user's consent or knowledge.
Web - is an abstract Internet space, in which a user can access multiple file types and archives connected by hyperlinks. See also HTML.
Worm (also known as I-Worm or Internet Worm) - is a self-replicating program that reproduces itself over a network. They can damage file systems and/or simply use up bandwidth. Worms generally use e-mail clients to replicate themselves over networks. Worms became infamous when Robert Morris at Cornell created one that shut down many Unix computers on the Internet in 1988. Recent worms are: CodeRed, Nimda and Klez.